Charge transfer, d-band modulation, and magnetoresistance in Pd-based alloys: Enhancing O ₂ adsorption and catalytic activity via surface engineering

Using density functional theory, this study probes Pd-based alloys and graphene-supported clusters that deliver both catalytic activity and magnetoresistance. The oxygen adsorption was on Pd 3 Fe and Pd 3 Ti clusters anchored to graphene quantum dots, with oxygen-driven surface segregation in Pd-Ti alloys. The clusters bind strongly to Graphene Quantum Dots (GQDs) and the Pd 2 Ti system shows the best adsorption energy of [Formula: see text]2.12[Formula: see text]eV, which promotes CO 2 activation by elongation of the C–O bond to 1.30[Formula: see text]Å. For Pd-Ti alloy surfaces, oxygen adsorption strongly favors Ti enrichment at the surface, most notably on the (110), due to charge redistribution and shifts in the d band center. Magnetic behavior tracks magnetoresistive response peaks at 90 ∘ , consistent with spin-dependent transport. These results connect oxygen chemistry, electronic structure, and magnetism, identifying Pd 2 Ti-based materials as multifunctional candidates for oxygen reduction and CO 2 conversion.